The immune system plays a critical role in our health. The importance of understanding the function of the immune system and learning how to modulate immunity to protect against or treat disease and infection cannot be overstated. Compounds that can modulate both the innate immune response to fight infection and modulate the humoral and cellular response to fight cancer are needed.
Cyclic dinucleotides (CDNs) have been found to have interesting immune-stimulatory properties. CDNs have the potential to promote protective immunity through a unique pathway using the cystolic danger sensor STING (STimulator of Interferon Genes) and its downstream transcription factors. CDNs produced by bacteria elicit an innate immune response that is critical for effective host defense against infection. Additional work has shown CDNs promote cellular and humoral immunity in vaccinated mice, thus creating an interest in developing CDN-based vaccine adjuvants. Unfortunately, as small molecules, CDNs are rapidly flushed from the injection site, leading to systemic inflammatory side effects. Therefore, there remains a need for strategies for delivering CDNs based on the response desired.